1. Field of the Invention
The present invention relates to a disk drive such as a hard disk drive (HDD). In particular, the invention relates to a disk drive comprising a disk and a ramp member located at a location outside the disk.
2. Description of the Prior Art
A head actuator is incorporated in a hard disk drive, for example. The head actuator includes an actuator arm allowed to swing around a support shaft along a predetermined path. When the actuator arm furthest swings in a normal direction outward in the radial direction of the magnetic recording disk, the actuator arm is positioned at the inoperative position. The tip end of the actuator arm is received on a ramp member. When the actuator arm swings from the inoperative position in the reverse direction opposite to the normal direction, the tip end of the actuator arm is released from support of the ramp member.
A so-called latch mechanism is often incorporated in the hard disk drive. The latch mechanism includes a lever supported on a first shaft for swinging movement. A weight is coupled to the lever. The weight is thus supported on the first shaft for swinging movement. When the lever swings around the first shaft from a neutral position based on the inertial force of the weight, the lever is contacted with a swinging member. Contact with the lever swinging in a first direction, or contact with the lever swinging in a second direction opposite to the first direction causes the swinging movement of the swinging member around a second shaft from an inoperative position. The swinging member is thus allowed to get into the predetermined path of movement of the actuator arm.
When impact of a fall serves to induce a sequential driving force in the normal and reverse directions in the hard disk drive, for example, the lever is forced to swing from the neutral position around the first shaft in the second direction based on the driving force in the normal direction. The swinging member swings around the second shaft from the inoperative position. The swinging member is thus allowed to get into the path of movement of the actuator arm. The actuator arm is held at the inoperative position. The actuator arm thereafter starts swinging back from the inoperative position based on the driving force in the reverse direction.
In this case, since the lever and the swinging member have already been positioned off the neutral and inoperative positions, respectively, the swinging movement of the lever and the swinging member cannot start from the neutral and inoperative positions. It takes a long way for the lever and the swinging member to reach the path of movement of the actuator arm. The actuator arm thus passes by the swinging member before the swinging member gets into the path of movement of the actuator arm. The swinging member cannot restrict the swinging movement of the actuator arm. The actuator arm is in this manner released from the support of the ramp member. A head slider at the tip end of the actuator arm thus collides against the surface of the magnetic recording disk. There is a possibility that the head slider gets damaged.